JP2006187306A - Biological signal processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological signal processor capable of easily performing the composite observation of biological optical signals and brain wave signals. <P>SOLUTION: The biological optical signals and measurement signals of brain waves are combined and displayed corresponding to the purpose of an observer by using a time course graph indicating the time change of signals, a time course map in which the time course graph is arranged at a measurement position, two-dimensional images, and the moving image display of the two-dimensional images, etc. Also, relation between two signals is mathematically processed and it is displayed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a biological signal processing apparatus, and more particularly to a biological signal processing apparatus for observing a biological optical signal and an electroencephalogram signal in combination.

  A living body light measurement device is a device that can easily measure blood circulation and hemodynamics in a living body by measuring hemoglobin change, with low restraint on a subject and without causing harm to the living body. Such a living body light measurement device is known as a device that measures the inside of a living body by irradiating the living body with light having a wavelength in the visible to infrared region and detecting the light that has passed through the living body (for example, a patent) Reference 1 and Patent Reference 2).

  Examples of clinical applications of this biological light measurement device include the activation state of hemoglobin change in the brain with the head as a measurement target, and measurement of local intracerebral hemorrhage. In addition, it is also possible to measure higher-order brain functions, such as movement, sensation, and thought, related to hemoglobin changes in the brain. This measurement is especially lightweight by attaching multiple probes for light irradiation and detection to the subject, so that the burden on the subject is small and the physical restraint is small. Conventionally, PET or high magnetic field MRI It has the feature that it can measure the distribution of advanced brain functions that could only be measured by the device.

  On the other hand, an electroencephalogram signal generated from a living body with a similar brain function activity has long been used as a means for diagnosing brain disease as a means for directly measuring nerve activity in the brain.

Both of these signals are signals associated with the same brain activity, but the physical mechanisms are different, so the information held by the signals is different, and the spatial and temporal characteristics are complementary. I came.
JP 57-115232 A JP-A 63-275323

  The simultaneous measurement of the electroencephalogram signal and the biological optical signal as described above is relatively easy because there is no physical mutual interference between the two signals. However, since the temporal and spatial characteristics of both are greatly different, It is also difficult for specialists to apply multiple observations to disease diagnosis.

  In particular, effective diagnostic information cannot be obtained efficiently only by displaying both signals individually in the conventional methods. For this reason, there is a need for a new signal analysis display means that allows an observer to easily understand both signals and to acquire new diagnostic information that cannot be obtained alone.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a biological signal processing apparatus that can easily perform combined observation of biological optical signals and electroencephalogram signals.

  In order to achieve the above object, the biological signal processing apparatus according to claim 1 is a state inside the subject calculated based on transmitted light obtained by irradiating the subject with light in the visible to infrared region. A first input means for inputting a biological optical signal indicating a change in association with a portion of the subject; and a brain activity signal calculated based on an electromagnetic signal generated by the brain activity of the subject. And second display means for inputting in association with the region, and display means for simultaneously displaying the input biological light signal and the input brain activity signal in association with the region of the subject.

  In the biological signal processing apparatus according to the first aspect, the biological optical signal and the brain activity signal are associated with the region of the subject and simultaneously displayed as a graphic, so that the combined observation of these signals can be easily performed.

  Signal display is based on temporal changes in biological optical signals and brain activity signals, relations with measurement positions of temporal changes in signals, distribution of signals at specific times and specific time zones, and time axis direction of such signal distributions Can be performed based on continuous display (moving image display).

  Further, the signal display may be performed in real time while measuring the signal, or may be performed offline after the measurement is completed.

  The biological signal processing apparatus according to claim 2 further includes means for designating a region of the subject based on an instruction input from an operator in the biological signal processing apparatus according to claim 1, wherein the display means It is characterized by displaying a biological light signal and a brain activity signal in the selected region.

  In the biological signal processing apparatus according to the second aspect, the relationship between the part of the subject and the signal can be grasped more easily.

  The biological signal processing apparatus according to claim 3 is the biological signal processing apparatus according to claim 1, wherein the image showing the biological optical signal in each part of the subject and the brain activity signal in each part of the subject are obtained. An image creating means for creating an image to be shown is further provided, and the display means displays the created image.

  In the biological signal processing apparatus according to the third aspect, the combined observation of the biological optical signal and the brain activity signal can be easily performed by image display.

  The biological signal processing device according to claim 4 is the biological signal processing device according to claim 3, wherein the display unit synthesizes and displays an image showing the biological optical signal and an image showing the brain activity signal. It is characterized by that.

  The biological signal processing device according to claim 5 is the biological signal processing device according to claim 3, wherein the display unit displays an image showing the biological optical signal and an image showing the brain activity signal in different regions. It is characterized by that.

  The biological signal processing apparatus according to claim 6 is the biological signal processing apparatus according to claim 3, wherein the image indicating the biological optical signal and the image indicating the brain activity signal are respectively displayed on the first layer and the second layer. The display unit further includes a projecting unit, and the display unit displays the first layer and the second layer in a three-dimensional manner.

  In the biological signal processing apparatus according to the sixth aspect, it is possible to easily grasp the signal measurement position while simultaneously displaying two images.

  The biological signal processing apparatus according to claim 7 is the biological signal processing apparatus according to any one of claims 3 to 6, further comprising means for calculating a relationship between the biological optical signal and the brain activity signal. The display means displays the calculated result.

  In the biological signal processing device according to the seventh aspect, the relationship between the biological optical signal and the brain activity signal can be grasped more easily.

  In the biological signal processing apparatus according to the present invention, it is possible to easily perform combined observation of a biological optical signal and an electroencephalogram signal.

  Hereinafter, preferred embodiments of the biological signal processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a configuration of a biological signal processing system 100 according to the present embodiment. The biological signal processing system 100 includes a biological light measurement device 300, an electroencephalogram measurement device 400, and a biological signal processing device 200 that inputs and processes and displays these signals.

  The biological signal processing apparatus 200 is an embodiment of the biological signal processing apparatus according to the present invention, and includes a data input unit 210, a data storage unit 220, a data processing unit 230, and a data display unit 240. .

  The time change signal of the subject's hemoglobin measured by the biological light measurement device 300 is input to the data input unit 210 and transferred to the data storage unit 220 for storage. Information indicating the position of each measurement point and measurement time information are also added to the data and transferred simultaneously.

  On the other hand, the change in the time signal from the electrode placed on the head of the same subject measured by the electroencephalogram measurement apparatus 400 is also input to the data input unit 210 together with the information indicating the measurement time and each measurement point, and the data It is transferred to the storage unit 220 and stored.

  The data processing unit 230 processes the data from these two devices in a complex manner based on the added measurement time and measurement position information, and displays the result on the data display unit 240.

  Data display may be performed in real time during measurement or offline after the measurement, but the display method presented below is applicable to both.

  In addition to displaying both data in real time and offline, only one of the biological light signal or electroencephalogram signal is used as real time data, and the other data is displayed using stored data. Observation of measurement can be facilitated.

The biological light signal and the electroencephalogram signal are signals at a plurality of measurement points on the scalp, and information indicating measurement positions is stored. The display form of each signal is as follows. 2. Time course map in which the time graph of time course graphic 2.1 showing the time change of the signal at each point is arranged at the measurement position. 2. Two-dimensional image constructed based on the average of the specific time or specific time range of the measurement signal at each point There are 3 two-dimensional image animations created with signals at specific times at each point. In the biological signal processing system 100, combined observation of the biological optical signal and the electroencephalogram signal can be easily performed by appropriately combining and displaying these according to the purpose of the observer.

  Here, the biological light measurement apparatus 300 will be described. In FIG. 2, the whole structure of the biological light measuring device 300 is shown. FIG. 3 shows the configuration of the main part of the biological light measurement device 300.

  In this example, an embodiment in which the inside of the cerebrum is imaged by irradiating and detecting light from the skin of the head, for example, is shown for the case where the number of measurement channels, that is, the number of measurement positions is twelve. However, the biological light measurement device 300 is not limited to the head as a measurement target, and can be implemented for other parts, and other than a living body.

  The light source unit 1 includes four optical modules 2. Each optical module is composed of two semiconductor lasers that emit light of two wavelengths, for example, 780 nm and 830 nm, in the visible to infrared wavelength region. These two wavelength values are not limited to 780 nm and 830 nm, and the number of wavelengths is not limited to two wavelengths. For the light source unit 1, a light emitting diode may be used instead of the semiconductor laser. All the eight semiconductor lasers included in the light source unit 1 are modulated by the oscillation unit 3 including eight oscillators having different oscillation frequencies.

  Here, the configuration in the optical module 2 will be described with reference to FIG. 4 taking the optical module 2 (1) as an example. The optical module 2 (1) includes semiconductor lasers 3 (1-a), 3 (1-b), and drive circuits 4 (1-a), 4 (1-b) for these semiconductor lasers. ing. Here, as for the characters in parentheses, numbers indicate the included optical module numbers, and a and b indicate symbols indicating wavelengths of 780 nm and 830 nm, respectively.

  In these semiconductor laser drive circuits 4 (1-a) and 4 (1-b), a DC bias current is applied to the semiconductor lasers 3 (1-a) and 3 (1-b), and the oscillator 3 By applying different frequencies f (1-a) and f (1-b), the light emitted from the semiconductor lasers 3 (1-a) and 3 (1-b) is modulated. As this modulation, the present embodiment shows the case of analog modulation by a sine wave, but of course, digital modulation by rectangular waves at different time intervals may be used.

  Light emitted from these semiconductor lasers is individually introduced into the optical fiber 6 by the condenser lens 5 for each semiconductor laser. The two-wavelength light introduced into each optical fiber is introduced into one optical fiber, for example, the irradiation optical fiber 8-1 by the optical fiber coupler 7 for each optical module. Two-wavelength light is introduced into the irradiation optical fibers 8-1 to 8-4 for each optical module, and light is emitted from four different irradiation positions on the surface of the subject 9 from the other end of these irradiation optical fibers. Is irradiated. The light that has passed through the subject is detected by detection optical fibers 10-1 to 10-5 that are arranged at five detection positions on the subject surface.

  The end faces of these optical fibers are in light contact with the surface of the subject. For example, the optical fiber is attached to the subject by a probe described in JP-A-9-149903.

  Here, FIG. 6 shows an example of the geometric arrangement of the irradiation positions 1 to 4 and the detection positions 1 to 5 on the subject surface. In this embodiment, the irradiation / detection positions are alternately arranged on a square lattice. At this time, assuming that the midpoint between adjacent irradiation / detection positions is a measurement position, in this case, there are 12 combinations of adjacent irradiation / detection positions, so the number of measurement positions, that is, 12 measurement channels.

  As this light irradiation / detection position arrangement, for example, Japanese Patent Laid-Open No. 9-149903 and Yuichi Yamashita et al., “Near-Infrared Light Topography Measurement System: Imaging of Absorber Localized in Scattering Medium (Near -infrared topographic measurement system: Imaging of absorbers localized in a scattering medium), 1996, Review of Scientific Instruments, Vol. 67, 730-732 (Rev. Sci. Instrum., 67, 730 (1996) )It is described in.

  Here, when the adjacent irradiation and detection position interval is set to 3 cm, the light detected at each detection position passes through the skin and skull, and has information on the cerebrum. For example, Pey Double McCormick ( PWMcCormic et al., “Intracerebral penetration of infrared light”, 1992, Journal of Neurosurgery, Vol. 76, pp. 315-318 (J. Neurosurg., 33, 315 (1992). )).

  From the above, if 12 measurement channels are set with the arrangement of the irradiation detection positions, the cerebrum can be measured in a 6 cm × 6 cm region as a whole. In this embodiment, the case where the number of measurement channels is 12 is shown for simplicity, but by further increasing the number of light irradiation positions and light detection positions arranged in a lattice shape, the number of measurement channels can be further increased. It is also possible to easily enlarge the measurement area.

  For example, FIG. 7 shows a light irradiation / detection position arrangement in 24-channel measurement. Further, the adjacent irradiation and detection position intervals are not limited to 3 cm, but can be appropriately changed according to the measurement site or the like.

  In FIG. 3, the reflected light captured by each of the detection optical fibers 10-1 to 10-5 is detected independently for each detection position, that is, for each detection optical fiber corresponding to each detection position. Detectors such as photodiodes 11-1 to 11-5 are used for detection. As this photodiode, an avalanche photodiode capable of realizing highly sensitive optical measurement is desirable. A photomultiplier tube may be used as the photodetector. After the optical signal is converted into an electric signal by these photodiodes, the modulation signal is selectively detected by, for example, a lock-in amplifier module 12 composed of a plurality of lock-in amplifiers, and modulated according to the irradiation position and wavelength. Selectively detect signals.

  In the present embodiment, a lock-in amplifier as a modulation signal detection circuit corresponding to the case of analog modulation is shown. However, when digital modulation is used, a digital filter or a digital signal processor is used for modulation signal detection.

  Here, a specific example of modulation signal separation will be described with reference to the block diagram of the lock-in amplifier module 12 shown in FIG. 5, taking the detection signal at the detection position 3 in FIG. 6, that is, the detection signal in the photodiode 11-3 as an example. To do. In “detection position 3”, light emitted from adjacent “light irradiation position 1”, “light irradiation position 2”, “light irradiation position 3”, and “light irradiation position 4”, that is, “measurement position 4” in FIG. ”,“ Measurement position 6 ”,“ Measurement position 7 ”, and“ Measurement position 9 ”are measurement targets.

  Here, the light detected by the photodiode 11-3 corresponds to light of each two wavelengths irradiated at “irradiation position 1”, “irradiation position 2”, “irradiation position 3”, and “irradiation position 4”. Modulation frequency f (1-a), f (1-b), f (2-a), f (2-b), f (3-a), f (3-b), f (4-a) , F (4-b), 8 signals. Therefore, the output signal of the photodiode 11-1 is distributed to eight places, and the eight lock-in amplifiers 13-9 to 13-16 using the eight modulation frequencies as reference signals are measured.

  Here, the input signal to each lock-in amplifier is, for example, that the frequency of the reference signal is f (1-a) in the lock-in amplifier 13-9, so that the light detected by the photodiode 11-1 is “ Only light having a wavelength of 780 nm irradiated at the irradiation position 1 ”, that is, light having a modulation frequency of f (1-a) can be selectively detected. Similarly, in other lock-in amplifiers, light having a specific irradiation position and wavelength can be selectively detected.

  In this way, the light detected at the other detection positions, that is, the detection signals from the other photodiodes 11-1, 2, 4, and 5 also have modulation frequencies corresponding to the respective irradiation positions and wavelengths adjacent to each other. On the other hand, by performing lock-in detection individually, it is possible to measure the detected light amounts for all measurement positions and wavelengths. In the case of the two wavelengths and the twelve measurement positions shown in this embodiment, the number of signals to be measured is 24. Therefore, the lock-in amplifier module 12 includes a total of 24 lock-in amplifiers.

  The analog output signals of these lock-in amplifiers 13-1 to 13-24 are converted into digital signals by the 24-channel analog-digital converter 14, respectively. These measurements are controlled by the control unit 17. Further, the measured signal is recorded in the recording unit 18.

  From this result, the processing unit 15 uses the detected light amount of two wavelengths for each measurement position, changes in oxygenated hemoglobin concentration and deoxygenated hemoglobin concentration associated with brain activity, and further, total hemoglobin as a total amount of these hemoglobin concentrations. Calculate the concentration change.

  For example, “Spatial and temporal analysis of human motor activity using noninvasive NIR topography” by JP-A-9-19408 and the aforementioned Atsushi Maki et al. 1995, Medical Physics, Vol. 22, pp. 1997-2005 (Medical physics, 22, 1997 (1995)), and the result is displayed on an image, for example, 2 Display as a dimensional image.

  On the other hand, the electroencephalogram measurement apparatus 400 can capture the neural activity of the brain as a unique signal at each point in the brain by attaching an electroencephalogram electrode to a predetermined part of the subject's head and observing the current derived therefrom. it can. There are two types of EEG signals: Evoked EEG, which measures 10-300ms seconds of early response by repeated stimulation, and Continuous EEG measurement, which measures waves continuously in a time landscape. Widely used in clinical practice.

  Signals measured by the biological light measurement device 300 and the electroencephalogram measurement device 400 are the temporal changes in the hemoglobin amount change at each measurement point in the biological optical signal, the electrical signal changes in each time in the electroencephalogram signal, and the repeated stimulation in the induction. With respect to the potential change in the time direction of the period, in the continuous method, mainly the vibration change of the electric signal over the entire measurement time is recorded and stored.

  Both of these signals include information on the subject's ID and other information, the measurement position, and information on the measurement time.

  In the following, a specific example of a procedure for displaying the information of the biological light signal and the electroencephalogram signal at the same time or mutually in a simple and easy-to-diagnose manner will be presented.

  FIG. 8 shows an example in which a two-dimensional image obtained by electroencephalogram measurement among the measured signals is displayed superimposed on an image showing the head of the subject. Further, the two-dimensional image of the biological light measurement is displayed on the two-dimensional image of the electroencephalogram measurement, and a hue different from the display of the two-dimensional image of the electroencephalogram measurement is used. Usually, in the two-dimensional image display as in this example, in addition to using monochrome shading, pseudo-shading by mixing two or more specific colors is used. In this example, in order to easily identify both two-dimensional images, For example, different pseudo colors are used such that one is red-blue phase and the other is yellow-green phase.

  Alternatively, the two-dimensional image of the electroencephalogram measurement may be displayed with pseudo-color shading, and the biological light signal may be plotted as a contour map using color lines not included in the pseudo-color.

  The vertical relationship between the two display layers may be reversed, and the vertical relationship may be arbitrarily designated according to the wishes of the observer. Furthermore, by making one of the two layers of the image transparent, the relationship between the two can be easily observed.

  In FIG. 9, when a desired observation position is selected from the two-dimensional image indicating the measurement positions of the electroencephalogram signal and the biological optical signal, two types of time are displayed at different positions from the position display image on the display screen together with the mark indicating the selection position. An example in which the course signals are displayed in parallel is shown [drawer screen].

  FIG. 10 displays the above-mentioned drawer screen on a two-dimensional image, and the two-dimensional distribution image and the relationship of temporal change of two signals can be easily displayed.

  FIG. 11 displays two layers of two-dimensional images as two layers having different heights in a three-dimensional space so that the measurement position can be easily identified while simultaneously displaying two types of two-dimensional images. The vertical relationship between the two display layers may be reversed, and the vertical relationship may be arbitrarily designated according to the wishes of the observer.

  FIG. 12 is a time course map screen for displaying a time course graph at a measurement position. The time course graph is displayed in parallel or superimposed on each of two types of time course graphs, and the relationship between both signals at each measurement point can be easily observed. it can.

  In the above display, two types of data are displayed in parallel or superimposed, and the observer determines the relationship between the signals, but if the relationship between the two signals is processed mathematically and displayed Furthermore, the burden on the observer can be reduced.

  FIG. 13 shows an example in which two data values representing the distribution of two types of signals are multiplied by two data values and the result is newly constructed and displayed as a composite image. As a result, the composite image is emphasized at a portion where the signals of both data increase simultaneously, thereby clearly presenting the relationship between the two signals.

  Here, for the calculation between the two signals, a function optimized theoretically or experimentally according to a desired observation phenomenon may be used. For example, as shown in FIG. 14, by standardizing both data at the maximum value and displaying them on a phase screen with two data as orthogonal axes, a graphic representing the time relationship between the two data is constructed. It is also possible to extract a parameter by obtaining and display it on a two-dimensional image.

  Thus, in biological signal processing system 100 according to the present embodiment, it is possible to easily perform combined observation of biological optical signals and brain waves.

It is a figure which shows the structure of the biological signal processing system which concerns on one embodiment of this invention. 1 is a diagram illustrating an overall configuration of a biological light measurement device according to an embodiment of the present invention. It is a figure which shows the principal part structure of the biological light measuring device concerning one embodiment of this invention. It is a figure which shows the structure of the optical module concerning one embodiment of this invention. 1 is a diagram illustrating a configuration of a lock-in amplifier module according to an embodiment of the present invention. FIG. It is a figure which concerns on one embodiment of this invention and shows the example of geometric arrangement of a light irradiation position and a light detection position. It is a figure which concerns on one embodiment of this invention and shows the other example of geometric arrangement of a light irradiation position and a light detection position. It is a figure which shows the example of the superimposition display of a two-dimensional image concerning one embodiment of this invention. It is a figure which shows the example of a measurement position display concerning one embodiment of this invention. It is a figure which shows the example of a drawer | drawing-out display according to one embodiment of this invention. It is a figure which shows the example of 2 layer display concerning one embodiment of this invention. It is a figure which shows the example of a map display concerning one embodiment of this invention. It is a figure which shows the example of the calculation between images in one embodiment of this invention. It is a figure which shows the example of a mutual phase display concerning one embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Biological signal processing system, 200 ... Biological signal processing apparatus, 210 ... Data input part, 220 ... Data storage part, 230 ... Data processing part, 240 ... Data display part, 300: biological light measurement device, 400: electroencephalogram measurement device

Claims (7)

A biological optical signal indicating a change in state inside the subject calculated based on transmitted light obtained by irradiating the subject with light in the visible to infrared region is input in association with the site of the subject. One input means;
A second input means for inputting a brain activity signal calculated based on an electromagnetic signal generated by the brain activity of the subject in association with a portion of the subject;
Display means for simultaneously displaying the input biological light signal and the input brain activity signal in association with the region of the subject;
A biological signal processing apparatus comprising:   2. The apparatus according to claim 1, further comprising means for designating a part of the subject based on an instruction input from an operator, wherein the display means displays a biological light signal and a brain activity signal at the designated part. Biological signal processing apparatus.   The image processing device further includes an image creating unit that creates an image showing the biological optical signal in each part of the subject and an image showing the brain activity signal in each part of the subject, and the display unit displays the created image. The biological signal processing apparatus according to claim 1.   The biological signal processing apparatus according to claim 3, wherein the display unit synthesizes and displays an image showing the biological optical signal and an image showing the brain activity signal.   The biological signal processing apparatus according to claim 3, wherein the display unit displays an image showing the biological optical signal and an image showing the brain activity signal in different regions.   The image processing apparatus further includes means for projecting the image indicating the biological light signal and the image indicating the brain activity signal on the first layer and the second layer, respectively, and the display means includes the first layer and the second layer as tertiary. 4. The biological signal processing apparatus according to claim 3, wherein the biological signal processing apparatus performs original display.   The living body according to any one of claims 3 to 6, further comprising means for calculating a relationship between the biological light signal and the brain activity signal, wherein the display means displays the calculated result. Signal processing device.

Images